Re: Defiant little girl...I have to tell my friend that her DD can't play with DS any

Can you open the conversation with some questions? Like,

"Tell me about Rosie's behavior at home..."
-or-
"Do you feel like Rosie listens to you well?"

I would let her tell you exactly what she sees and doesn't see happening. From that you can decide how blunt you should be.

a) There's a good chance Rosie's mom is frustrated by her behavior, and if she expresses this to you then you can sympathize, tell her that these are the reasons that you don't feel capable of watching Rosie in your home any longer, and then lead into your concerns about how extreme her behavior can be.

b) If she asserts that Rosie is a perfect angel and oh by the way, she's writing a book on parenting, then you know there isn't any use telling her much. She would probably be shocked and offended if you told her Rosie's behavior was abnormal, so you're better off telling her you just aren't as talented a mother as she is and it's a shame Rosie can't come over any more, but you clearly aren't able to bring out the best in her perfect darling.